Air suspension systems for load carrying prime mover vehicles can include as many as eight air suspension bags supporting the two driven axles in pairs on either side of each axle. In one well-known prime mover, the pairs of air bags are connected by a common large diameter air lines extending between correspondingly positioned air bags on adjacent axles.
The common air lines are each connected by an air line to a control valve which controls the air supply to the common air lines to adjust the inflation of the air bags to ensure that the prime mover is kept level as it is driven over variable road conditions.
In other air suspension systems, such as the Hendrickson HAS Series suspension, each axle is supported at either side by a single large air bag mounted on a frame hanger to which the axle is connected.
While the known air suspension systems may be adequate for slowly changing road conditions, they are not sufficiently responsive to rapidly changing conditions such as are experienced in cornering and on rough sections of road. As a result the vehicle becomes unstable, reducing driver control, increasing driver fatigue, causing increased tyre wear and potential damage to the freight.